A microprocessor-based one dimensional optical data processor for spatial frequency analysis

A high degree of accuracy was obtained in measuring the spatial frequency spectrum of known samples using an optical data processor based on a microprocessor, which reliably collected intensity versus angle data. Stray light control, system alignment, and angle measurement problems were addressed and solved. The capabilities of the instrument were extended by the addition of appropriate optics to allow the use of different wavelengths of laser radiation and by increasing the travel limits of the rotating arm to + or - 160 degrees. The acquisition, storage, and plotting of data by the computer permits the researcher a free hand in data manipulation such as subtracting background scattering from a diffraction pattern. Tests conducted to verify the operation of the processor using a 25 mm diameter pinhole, a 39.37 line pairs per mm series of multiple slits, and a microscope slide coated with 1.091 mm diameter polystyrene latex spheres are described

Carbon thin film thermometry

The work concerning carbon thin film thermometry is reported. Optimum film deposition parameters were sought on an empirical basis for maximum stability of the films. One hundred films were fabricated for use at the Marshall Space Flight Center; 10 of these films were given a precise quasi-continuous calibration of temperature vs. resistance with 22 intervals between 5 and 80 K using primary platinum and germanium thermometers. Sensitivity curves were established and the remaining 90 films were given a three point calibration and fitted to the established sensitivity curves. Hydrogen gas-liquid discrimination set points are given for each film

WASP-1: A lithium- and metal-rich star with an oversized planet

In this paper we present our results of a comprehensive spectroscopicanalysis of WASP-1, the host star to the exoplanet WASP-1b. We derive T_eff = 6110 +/- 45 K, log g = 4.28 +/- 0.15, and [M/H] = 0.23 +/- 0.08, and also a high abundance of lithium, log n(Li) = 2.91 +/- 0.05. These parameters suggests an age for the system of 1-3 Gyr and a stellar mass of 1.25-1.35 M_sun. This means that WASP-1 has properties very similar to those of HD 149026, the host star for the highest density planet yet detected. Moreover, their planets orbit at comparable distances and receive comparable irradiating fluxes from their host stars. However, despite the similarity of WASP-1 with HD 149026, their planets have strongly different densities. This suggests that gas-giant planet density is not a simple function of host-star metallicity or of radiation environment at ages of ~2 Gyr.Comment: Accepted for publication in MNRAS. 6 pages, 4 figure

UV Spectroscopy of AB Doradus with the Hubble Space Telescope. Impulsive flares and bimodal profiles of the CIV 1549 line in a young star

We observed AB Doradus, a young and active late type star (K0 - K2 IV-V, P= 0.514 d) with the Goddard High Resolution Spectrograph of the post-COSTAR Hubble Space Telescope with the time and spectral resolutions of 27 s and 15 km, respectively. The wavelength band (1531 - 1565 A) included the strong CIV doublet (1548.202 and 1550.774, formed in the transition region at 100 000 K). The mean quiescent CIV flux state was close to the saturated value and 100 times the solar one. The line profile (after removing the rotational and instrumental profiles) is bimodal consisting of two Gaussians, narrow (FWHM = 70 km/s) and broad (FWHM =330km/s). This bimodality is probably due to two separate broadening mechanisms and velocity fields at the coronal base. It is possible that TR transient events (random multiple velocities), with a large surface coverage, give rise to the broadening of the narrow component,while true microflaring is responsible for the broad one. The transition region was observed to flare frequently on different time scales and magnitudes. The largest impulsive flare seen in the CIV 1549 emission reached in less than one minute the peak differential emission measure (10**51.2 cm-3) and returned exponentially in 5 minutes to the 7 times lower quiescent level.The 3 min average line profile of the flare was blue-shifted (-190 km/s) and broadened (FWHM = 800 km/s). This impulsive flare could have been due to a chromospheric heating and subsequent evaporation by an electron beam, accelerated (by reconnection) at the apex of a coronal loop.Comment: to be published in AJ (April 98), 3 tables and 7 figures as separate PS-files, print Table 2 as a landscap

A Study of the Effect of Blended Coarse Aggregate on Air Entrained Concrete

This research with combined coarse aggregates in cement concrete was initiated at the request of the Director of Design as a direct result of the condition study made by the Division of Design in 1945. In the report on this study it was shown that on the basis of averages pertaining to 80 projects with crashed limestone totalling about 395 miles in length, and 70 projects with Ohio River Gravel totalling approximately 410 miles in length, the service record for pavements with the river gravel was far inferior to that of pavements containing limestone coarse aggregate. Specifically, the summary of data showed that pavements with the gravel had an average of seven times as many outside corner breaks, more than eight times as many inside corner breaks, and almost eleven times as many blow-ups per mile as the pavements with crushed lime stone; furthermore, the average transverse crack and joint interval in the former was only about 0. 6 as long as that in the latter. Such rating was irrespective of age, design, subgrade conditions, separate sources of aggregates, and other factors which in the total analysis were considered individually but which could not be isolated as influences in combination with the coarse aggregates. Naturally, the effect of one or all of these factors could reduce the disparity in performance as related to aggregates alone, nevertheless, the contrast was so pronounced that some measures for obtaining parity of concrete with the different aggregates were considered desirable. As an absolute minimum, research to determine whether results of field observations would be reflected in laboratory tests was proposed. Accordingly, this project was established through an outline or working plan prepared on May 18, 1946. Two corrective measures, air entrainment and blending of aggregates, were the primary bases upon which the research was founded. Results from many investigations - later summarized in a comprehensive report - had indicated that air entrainment had been beneficial to concrete in almost every experiment, and that the greatest improvement in quality of concrete had occurred when the coarse aggregates were inherently of lowest quality. Similarly, blending of aggregates as a means for off-setting detrimental properties of one of the components had been used successfully in other states, an outstanding example of this being in Kansas where aggregates are quite variable and satisfactory sources are far from evenly distributed throughout the state. (A copy of the Supplemental Specification developed in Kansas is appended to this report.) Since air entrainment was due to become a. standard in concrete for pavements, interest was centered on the possible benefits or detriments of combined aggregates and the proportions in which they should be combined in order to provide the best concrete within practicable limits of economy on actual construction jobs

Study of the Effect of Blended Coarse Aggregate on Air Entrained Concrete

This research with combined coarse aggregates in cement concrete was initiated at the request of the Director of Design as a direct result of the condition study made by the Division of Design in 1945. In the report on this study it was shown that on the basis of averages pertaining to 80 projects with crushed limestone totalling about 395 miles in length, and 70 projects with Ohio River Gravel totalling approximately 410 miles in length, the service record for pavements with the river gravel was far inferior to that of pavements containing limestone coarse aggregate. Specifically, the summary of data showed that pavements with the gravel had an average of seven times as many outside corner breaks, more than eight times as many inside corner breaks, and almost elevent time sas many blow-ups per mile as the pavements with crushed limestone; furthermore, the average transverse crack and joint interval in the former was only about 0.6 as long as that in the latter

Research and development of superconducting thin films Final report, 15 Dec. 1965 - 15 Dec. 1966

Superconducting niobium thin film productio

Coronal structure of the cTTS V2129 Oph

The nature of the magnetic coupling between T Tauri stars and their disks determines not only the mass accretion process but possibly the spin evolution of the central star. We have taken a recently-published surface magnetogram of one moderately-accreting T Tauri star (V2129 Oph) and used it to extrapolate the geometry of its large-scale field. We determine the structure of the open (wind-bearing) field lines, the closed (X-ray bright) field lines and those potentially accreting field lines that pass through the equatorial plane inside the Keplerian co-rotation radius. We consider a series of models in which the stellar magnetic field is opened up by the outward pressure of the hot coronal gas at a range of radii. As this radius is increased, accretion takes place along simpler field structures and impacts on fewer sites at the stellar surface. This is consistent with the observed variation in the Ca II IRT and HeI lines which suggests that accretion in the visible hemisphere is confined to a single high-latitude spot. By determining the density and velocity of the accretion flows, we find that in order to have most of the total mass accretion rate impacting on a single high-latitude region we need disk material to accrete from approximately 7R*, close to the Keplerian co-rotation radius at 6.8R*. We also calculate the coronal density and X-ray emission measure. We find that both the magnitude and rotational modulation of the emission measure increase as the source surface is increased. For the field structure of V2129 Oph which is dominantly octupolar, the emission forms a bright, high-latitude ring that is always in view as the star rotates. Since the accretion funnels are not dense enough to cause significant scattering of coronal X-ray photons, they provide only a low rotational modulation of around 10% at most.Comment: 10 pages, 9 figure

Instrumentation for hydrogen slush storage containers

Hydrogen liquid and slush tank continuous inventory during ground storag

Laminar-flow flight experiments

The flight testing conducted over the past 10 years in the NASA laminar-flow control (LFC) will be reviewed. The LFC program was directed towards the most challenging technology application, the high supersonic speed transport. To place these recent experiences in perspective, earlier important flight tests will first be reviewed to recall the lessons learned at that time